WIDE-RANGE, WIDE-ANGLE, ROTATABLE COMPOUND ZOOM

摘要

A compact zoom lens system providing a wide-range, ultra-wide angle optionally rotatable compound zoom is disclosed. In one embodiment, the optical design is comprised of an NPP kernel followed by a PP relay with four independently moving groups, two on each side of an intermediate image. The front group is stationary with respect to the image plane, as are two fold prisms. The kernel has a zoom ratio of about 2:1, and the zoom relay has a magnification ratio of about 4:1, giving a total zoom ratio of about 8.6:1. The PP relay is comprised of two independently moving positive groups. The focal lengths covered by the zoom range have a 35mm still camera equivalent of about 21mm to 180mm. The aperture of the system ranges from about f/2.8 to f/6.3, but is constant at about f/2.8 from about 3mm through 6.2mm focal length.